So powerful in fact that two of the above five are illegal to play in Modern
If you have fewer than four creature cards in your graveyard at that point, the ability won't have any effect.

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Ognis, the Dragon's Lash has you choosing haste over the +1/+1 counter which also makes for a compelling argument in favor of riot giving you the power of choice
Ruby/Emerald is a great deck for tacticians interested in countering opponents, with an arguably higher skill ceiling than Amber/Amethyst that can make it a real power deck in the right hands